Protected shafting



2 Sheets-Sheet l 27 I rr/b2? 5502? .E [TEL/2 G. C. DAVIS PROTECTED SHAFTING Filed Jan. 9, 1934 J 5 Z M a? 1527 5-- Dec. 3, 1935.

Dec. 3, 1935. r DAVIS 2,023,266

PROTECTED SHAFTING Filed Jan. 9, 1934 2 Sheets-Sheet 2 jnL/ETv/ba 550F575 [175M25 Patented Dec. 3, 1935 PATENT OFFICE PROTECTED SHAFTING George 0. Davis, Dallas, Tex., assignor to The B. F. Goodrich Company, New York, N. Y., a corporation of New York Application January 9, 1934, Serial No. 705,913

4 Claims. (01. 308-4) This invention relates to protected shafting, such for example as the drill pipe assembliesused in rotary drilling rigs for oil well drilling.

Such pipe assemblies heretofore have been protected from abrasive contact with the sides of the well casing by guard structures entirely encircling the drill pipe or joints thereof, and in these devices contractile force and. frictional gripping of the annular structures upon the pipe or joint has usually been relied upon to hold the structures in place. This construction has not been wholly satisfactory, however, the mounting of the guards being, inadequately secure under some of' the more severe conditions of use, and the annular form of the guards in some cases being objectionable in impeding the flow of the drilling fluid upwardly along the outside of the pipe, and the structure being awkward to assemble and disassemble.

The chief objects of this invention are to provide a protected drill pipe assembly or other shafting in which the guard structures do not need to extend around the entire circumference thereof and yet are securely mounted thereon, to provide adequate protection for the pipe assembly with a minimum of flow-impeding structure at the outside thereof, to provide simplicity of structure, and to provide for conveniently assembling and replacing the guard elements.

These and further objects will be apparent from the following description, reference being had to the accompanying drawings in which:

Fig. l is an elevation, with parts broken away and in section, of a protected drill pipe assembly constructed according to and embodying the invention in its preferred form.

Figs. 2 and 3 are sections along the lines 2-2 and 3-3, respectively, of Fig. 1.

Fig. 4 is a view like Fig. 1, but showing a modified construction.

Figs. 5 and 6 are sections along the lines 55 and 66, respectively, of Fig. 4.

Fig. 7 is a perspective view of a guard element of Figs. 4 and 6.

Figs. 8, 9 and 10 are perspective views of modified forms of guard elements.

' Referring to Fig. 1, the assembly comprises drill pipe sections In and II which are detachably coupled by threaded joint sections 12 .and I3 in a manner well known in the art.

The improved guards may be mounted directly upon the drill pipe if desired, but it is preferred to mount them upon the joint sections which protrude radially beyond the pipe sections and accordingly are most vulnerable to contact with the well casing while the stem is rotated and fed therein during the drilling.

Each guard comprises a pad I4, preferably of resilient. rubber, having at its inner face a pair of stiff attaching plates l5, I6, which may be 5' metal, having faces preferably matching the contour of the portion of the cylindrical drill shaft on which the guard is mounted, and being held by the rubber of the pad, preferably by vulcanized adhesion, so as to constitute with the latter an 10 integral unit that is flexible in the manner of a hinge and sti'fily stretchable along the zone I! of" the adjoining margins of the two plates l5, Hi.

The plates I5 and I6 have a pair of lugs l8 and 19, respectively which are circumferentially 15 spaced apart in the mounted position of the guard and are inclined toward each other at an acute angle and adapted to fit in corresponding grooves or recesses cut into the wall of the joint section, as is shown most clearly in Figs. 2 and 3, to resist movement of the guard away from its intended position. Desirably the plates are provided also with lugs 20, 20, and 2|, 2| which are longitudinally spaced apart with relation to the joint section and seat in grooves 22, 22 extending into the 25 wall of the section in the radial direction so as to resist movement of the guard longitudinally of the section and to resist rotative movement of the guard but not necessarily to interlock with the section.

The lugs may be cast, struck-out or otherwise suitably formed on the plates, and the grooves in the wall of the joint section may be conveniently formed simply as saw cuts therein. If desired, the plates I5 and I6 may be perforated, as at 40, 40, for the sake of a strong attachment to the rubber of the pad.

For the operation of mounting the guard upon the section either the lug l8 or I 9 is inserted in its q recess and that half of the guard is laid flat against the wall of the section, the hinge portion I! of the guard permitting the necessary flexure thereof to effect this while the other lug still is unseated in its recess. The latter lug is then engaged by a suitable tool, such as one having a hooked end, and is then drawn to its recess and released therein, the rubber at the hinge ll stretching to permit this and recoiling when the lug has been seated to hold the guard thus anchored. During this assembly operation the other lugs 20, 20, and 21, 2| will be positioned in their respective slots in the wall of the section. Removal of the guard, as for replacement, may be effected by prying it away from the wall at a margin near one of the lugs H3 or l9.

In the embodiment of Figs. 4-7, the guard members are in the form of strips 30, 30 and are independently secured in the circumferentially spaced relation about the pipe assembly by means of undercut or dovetailed portions 3 I, 3|, provided on the strips fitting within corresponding grooves cut longitudinally in the wall of the desired portion of the assembly. Preferably these strips are mounted on the male and female joint sections of the assembly as shown in Fig. 4, the grooves opening at the adjoining end faces 32, 33 of the sections and terminating short of the other ends of the sections so that when the strips are inserted and the sections coupled, movement of the strips in all directions will be prevented.

As it is preferred to make the outer face of the guard strips of resilient rubber for most effective guarding, the inner interlocking portion of the strip may be stiffened for more effective anchorage in the grooves, as by the use of a harder compound in this portion of the strip, as shown in Figs. 4-7, or by a stiifening element secured to the strip, which may be of fiber board or metal as at 34 in Fig. 8, or fabric plies as at 35 in Fig. 10. In some cases it is satisfactory to use a wholly resilient rubber strip without stiffening means as shown in Fig. 9. make the undercut portion 36 of the strip slightly larger than the groove it is to occupy so that it will exert pressure against the side walls of the groove to resist displacement.

In associations where it is not feasible or convenient to block the ends of the grooves as in Fig. 1, the strips may be anchored by means of In such cases it is preferred to tap screws extending through the strips and into the wall of the section, and for this purpose the strips may be formed with apertures 31, 31, as shown in Fig. 8.

I claim:

1. A shafting assembly comprising a guard unit having a pair of lugs each projecting obliquely from a face of the unit in the direction of the other lug, and a shafting section formed in its wall with recesses of such shape and location as to house said lugs in anchored relation of the guard unit to the section.

2. A shafting assembly as defined in claim 1 in which the guard unit comprises a resiliently stretchable portion connecting the portions having the lugs.

3. A shafting assembly as defined in claim 1 in which the guard unit comprises a resilient rubber pad having a pair of plates bonded to a face thereof and conforming to the surface of the section, each of said plates having one of the said lugs projecting therefrom.

4. A shafting assembly comprising a pair of joint sections mating in end to end relation, one of said sections being formed in its outer surface with an undercut, longitudinally extending groove open at the mating end of the section and terminating short of the other end of the section, and a guard unit having an anchoring portion fitting within the undercut groove and being restrained from movement through the open end of the groove by the end face of the mating joint section.

GEORGE C. DAVIS. 

